Method for allocating power in an electrical power system architecture

ABSTRACT

An electrical power system architecture and method for allocating power includes a power distribution bus configured to receive power generated by a first engine having a first generator and a second generator, a first set of electrical buses connected with the power distribution bus and associated with the first engine, and a second set of electrical buses configured to selectively connect with the power distribution bus.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.15/331,111 filed Oct. 21, 2016, which is incorporated herein in itsentirety.

TECHNICAL FIELD

The disclosure relates to a method and apparatus for starting an engineduring flying operations of an aircraft.

BACKGROUND OF THE INVENTION

Turbine engines, and particularly gas turbine engines, also known ascombustion turbine engines, are rotary engines that extract energy froma flow of combusted gases passing through the engine onto a multitude ofturbine blades. Gas turbine engines have been used for land and nauticallocomotion and power generation, but are also often used foraeronautical applications such as for airplanes, including helicopters.In airplanes, gas turbine engines are used for propulsion of theaircraft.

Gas turbine engines can have two or more spools, including a lowpressure (LP) spool that provides a significant fraction of the overallpropulsion system thrust, and a high pressure (HP) spool that drives oneor more compressors and produces additional thrust by directing exhaustproducts in an aft direction.

Gas turbine engines also usually power a number of different accessoriessuch as generators, starter/generators, permanent magnet alternators(PMA), fuel pumps, and hydraulic pumps, e.g., equipment for functionsother than propulsion. For example, contemporary aircraft needelectrical power for avionics, motors, and other electric equipment. Agenerator coupled with a gas turbine engine will convert the mechanicalpower of the engine into electrical energy needed to power accessories.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present disclosure relates to a method for restartinga non-operational engine of a flying aircraft, the method includingdisabling a set of electrical loads associated with the non-operationalengine from a power distribution bus except for a subset of essentialelectrical loads associated with the non-operational engine, selectivelyallocating a combined power output between at least two generatorsystems driven by at least one operational engine of the flyingaircraft, and restarting the non-operational engine by way of amechanically connected starter/generator supplied with at least aportion of the combined power output, wherein the selectively allocatingthe combined power output is based at least on the summation of a firstpower demand for a set of electrical loads associated with theoperational engine, a second power demand for the subset of essentialelectrical loads associated with the non-operational engine, and a thirdpower demand for the restarting the non-operational engine.

In another aspect, the present disclosure relates to an electrical powersystem architecture, including a power distribution bus configured toreceive power generated by a first engine having a first generatorsystem and a second generator system, a first set of electrical busesconnected with the power distribution bus and associated with the firstengine, a second set of electrical buses configured to selectivelyconnect with the power distribution bus, including at least an essentialbus, and associated with a second engine, and a share regulatorconfigured to provide a set of share ratios values to the firstgenerator system and the second generator system, and configured toreceive an operational status of the second engine, wherein, uponreceipt of non-operational status of the second engine, the powerdistribution bus is configured to selectively disconnect the second setof electrical buses except for the essential bus, and the shareregulator is configured to provide the set of share ratio values to thefirst generator system and second generator system selected to enabledthe first and second generator systems to share allocation of powergeneration sufficient to: energize the first set of electrical buses,energize the essential bus, and to restart the non-operational secondengine.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top down schematic view of the aircraft and powerdistribution system of an aircraft.

FIG. 2 is a schematic block diagram of an electrical power systemarchitecture for the aircraft of FIG. 1, in accordance with variousaspects described herein.

FIG. 3 is a schematic block diagram of an electrical power systemarchitecture of FIG. 2, wherein one of the engines is non-operational,in accordance with various aspects described herein.

FIG. 4 is a schematic block diagram of an electrical power systemarchitecture for the aircraft of FIG. 3, wherein the non-operationalengine is restarting, in accordance with various aspects describedherein

FIG. 5 is an example a flow chart diagram of demonstrating a method offor allocating power in the electrical power system architecture, inaccordance with various aspects described herein.

FIG. 6 is a method of restarting a non-operational engine, in accordancewith various aspects described herein.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The described embodiments of the present innovation are directed to amethod and apparatus associated with a modular power distribution rack.One example environment where such a method and apparatus can be usedincludes, but is not limited to, a power distribution system for anaircraft. While this description is primarily directed toward a powerdistribution system for an aircraft, it is also applicable to anyenvironment using a nodal-based power distribution system where inputpower is received, acted upon (if necessary), e.g., converted ormodified, and distributed to one or more electrical loads.

While “a set of” various elements will be described, it will beunderstood that “a set” can include any number of the respectiveelements, including only one element. Connection references (e.g.,attached, coupled, connected, decoupled, disconnected, and joined) areto be construed broadly and can include intermediate members between acollection of elements and relative movement between elements unlessotherwise indicated. As such, connection references do not necessarilyinfer that two elements are directly connected and in fixed relation toeach other. In non-limiting examples, connections or disconnections canbe selectively configured to provide, enable, disable, or the like, anelectrical connection between respective elements. Non-limiting examplepower distribution bus connections or disconnections can be enabled oroperated by way of switching, bus tie logic, or any other connectorsconfigured to enable or disable the energizing of electrical loadsdownstream of the bus. The exemplary drawings are for purposes ofillustration only and the dimensions, positions, order and relativesizes reflected in the drawings attached hereto can vary.

As illustrated in FIG. 1, an aircraft 10 is shown having at least onegas turbine engine, shown as a left engine 12 and a right engine 14.Alternatively, the power system can have fewer or additional enginesystems. The left and right engines 12, 14 can be substantiallyidentical, and can further include at least one power source, such as anelectric machine. As shown, the power sources can include a firstgenerator 18 and a second generator 19 corresponding to the left engine12, and the power sources can include a third generator 36 and a fourthgenerator 38 corresponding to the right engine 14. In one non-limitingconfiguration, the set of generators 18, 19, 36, 38 can be selectivelyconfigured to generate approximately 200 kW of electrical power. Theaircraft is shown further having a set of power-consuming components, orelectrical loads 20, such as for instance, an actuator load, flightcritical loads, and non-flight critical loads. The set of electricalloads 20 are electrically coupled with at least one of the generators18, 19, 36, 38 via a power distribution system including, for instance,power transmission lines 22 or bus bars, and power distribution nodes16. It will be understood that the illustrated embodiment of thedisclosure of FIG. 1 is only one non-limiting example of a powerdistribution system, and many other possible embodiments andconfigurations in addition to that shown are contemplated by the presentdisclosure. Furthermore, the number of, and placement of, the variouscomponents depicted in FIG. 1 are also non-limiting examples ofembodiments associated with the disclosure.

In the aircraft 10, the operating left and right engines 12, 14 providemechanical energy which can be extracted, typically via a spool or setof spools, to provide a driving force for the generators 18, 19, 36, 38.The generators 18, 19, 36, 38, in turn, generate power, such as AC or DCpower, and provides the generated power to the transmission lines 22,which delivers the power to the power distribution nodes 16, positionedthroughout the aircraft 10. The power distribution nodes 16 receive theAC or DC power via the transmission lines 22, and can provide switching,power conversion, or distribution management functions, as needed, inorder to provide the desired electrical power to the set of electricalloads 20 for load operations.

Example power distribution management functions can include, but are notlimited to, selectively enabling or disabling the delivery of power toparticular electrical loads 20, depending on, for example, availablepower distribution supply, criticality of electrical load 20functionality, or aircraft mode of operation, such as take-off, cruise,or ground operations. Additional management functions can be included.In this sense, the set of electrical loads 20 can include subsets ofelectrical loads 20, subdivided by criticality or assignment to a leftor right engine 12, 14, or a respective generator 18, 19, 36, 38.Additional aspects of the subdivision of electrical loads 20 can beincluded. Furthermore, additional power sources for providing power tothe electrical loads 20, such as additional engines 12, 14, emergencypower sources, ram air turbine systems, starter/generators, orbatteries, can be included. It will be understood that while oneembodiment of the invention is shown in an aircraft environment, theinvention is not so limited and has general application to electricalpower systems in non-aircraft applications, such as other mobileapplications and non-mobile industrial, commercial, and residentialapplications.

Aspects of the disclosure can include to allocating power generationamong generators 18, 19, 36, 38, between a single engine 12, 14, orbetween a set of generators 18, 19, 36, 38 of different engines 12, 14,or among a set generators 18, 19, 36, 38 among a set of engines 12, 14.

FIG. 2 is a schematic block diagram of an electrical power systemarchitecture 30 in accordance with various aspects described herein. Thesystem architecture 30 includes multiple generator systems, shown hereinas including at least the left engine system 32 including the leftengine 12, a first generator 18, and a second generator 19, and a rightengine system 34 including the right engine 14, the third generator 36,and the fourth generator 38. Non-limiting aspects of the disclosure canbe included wherein at least one generator 18, 19, 36, 38 can include astarter/generator, that is, a generator that is capable or enabled toprovide a starting function for an operably coupled engine 12, 14 orengine system 32, 34 when supplied with a starting power. Specificmethods or configurations of starter/generators are not germane to theaspects of the disclosure. Non-limiting configurations can be envisionedwherein at least one generator 18, 19, 36, 38 per engine 12, 14 orengine system 32, 34 is a starter/generator. Additionally, non-limitingaspects of the disclosure can be applied regardless of whether thegenerator 18, 19, 36, 38 is configured to generate alternating current(AC) power or direct current (DC) power.

Aspects of the disclosure can be included wherein the first generator 18connects to a high pressure (HP) spool 48 of the left engine 12 by wayof a HP spool gearbox 52 while the second generator 19 connects to a lowpressure (LP) spool 50 of the left engine 12 by way of a LP spoolgearbox 54. In this sense, the mechanical power provided by HP spool 48operably drives the first generator 18 and the mechanical power providedby the LP spool 50 operably drives the second generator 19 forelectrical power generation. The HP spool gearbox 52 and LP spoolgearbox 54 can be selected, configured, or operable to enable a gearratio to step-up or step-down a mechanical rotation speed of therespective HP spool 48 or LP spool 50 such that the connected generators18, 19 and operably utilize the mechanical power to generate electricalpower. Aspects of the disclosure can be included wherein at least one ofthe HP spool gearbox 52 or LP spool gearbox 54 is optional.

The first generator 18 and second generator 19 are shown in parallelarrangement and configured to provide respective generator power outputsto a first Inverter/Converter/Controller (ICC) 40 or second ICC 42. Thefirst and second ICCs 40, 42 are further connected with a powerdistribution bus 44. As illustrated, the first generator 18 and thefirst ICC 40 can be included as part of a first generator system 85 andthe second generator 19 and the second ICC 42 can be included as part ofa second generator system 85. Also as shown, the first and second ICCs40, 42 can be selectively connected with the power distribution bus 44by way of respective selectively coupling links 46. As described herein,an ICC can be configured to operably enable or selectively implementinverting, converting, controlling, or the like, a first power receivedby the ICC to a second power supplied by the ICC. In this sense, theICCs can operably convert a first power to a different second power.Converting can include, but is not limited to, altering an AC frequency,stepping up or stepping down an AC or DC voltage, AC-to-DC powerconversion, DC-to-AC power conversion, or the like. Additionally,non-limiting aspects of the disclosure can be included wherein at leastone ICC 40, 42 can be configured to provide bi-directional oruni-directional power converting. In this sense, at least one ICC 40, 42can be included that can controllably or operably convert power suppliedby a generator 18, 19, 36, 38 to the power distribution bus 44, as wellas controllably or operably convert power supplied by the powerdistribution bus 44 to a generator 18, 19, 36, 38, such as astarter/generator. Non-limiting aspects of the disclosure can beincluded wherein the set of generators 18, 19 generate electrical power(AC or DC power) that is altered by way of the respective ICC 40, 42, toa common power supply for the power distribution bus 44. In one example,the common power supply can include 270 volts DC, ±270 volts DC, 115volts AC at 400 Hertz, or 230 volts AC at 400 Hertz. Additional commonpower supplies can be included.

Non-limiting aspects of the right engine system 34 can be similar toaspects of the left engine system 32, unless otherwise noted. Thus,aspects of the disclosure can be further included wherein the thirdgenerator 36 connects to a high pressure (HP) spool 56 of the rightengine 14 by way of a HP spool gearbox 60 while the fourth generator 38connects to a low pressure (LP) spool 58 of the right engine 14 by wayof a LP spool gearbox 62. In this sense, the mechanical power providedby HP spool 56 operably drives the third generator 36 and the mechanicalpower provided by the LP spool 58 operably drives the fourth generator38 for electrical power generation. Aspects of the disclosure can beincluded wherein at least one of the HP spool gearbox 60 or LP spoolgearbox 62 is optional.

The third generator 36 and fourth generator 38 are shown in parallelarrangement and configured to provide respective generator power outputsto a third ICC 64 or fourth ICC 66. The third and fourth ICCs 64, 66 arefurther connected with the power distribution bus 44. As illustrated,the third generator 36 and the third ICC 64 can be included as part of athird generator system 89 and the fourth generator 38 and the fourth ICC66 can be included as part of a fourth generator system 91. Also asshown, the third and fourth ICCs 64, 66 can be selectively connectedwith the power distribution bus 44 by way of respective selectivelycoupling links 46. Similar to the left engine system 32, non-limitingaspects of the disclosure can be included wherein at least one ICC 64,66 can be configured to provide bi-directional or uni-directional powerconverting.

The power distribution bus 44 can be further connected by way of a setof selectively coupling links 46 to a set of additional electrical loadsor electrical buses 71 utilized to selectively supply power to the setof electrical loads (not shown). As shown, the set of additionalelectrical buses 71 can include, but is not limited to, a left main bus70, a left essential bus 72, a left power conversion bus 74, a leftbattery bus 76, a right main bus 78, a right essential bus 80, a rightpower conversion bus 82, and a right battery bus 84. As shown, the setof electrical buses 71 can be arranged, categorized, organized, orselectively supplied by electrical power based upon an assignment to arespective engine system 32, 34 (e.g. left or right), or aclassification of electrical loads (e.g. main bus loads, essential busloads, etc.). In non-limiting aspects of the disclosure, the left enginesystem 32, or the generators 18, 19 associated with the left engine 12,can be primarily responsible for supplying a sufficient amount of energyfor powering the “left” set of electrical buses 70, 72, 74, 76 undernormal operating conditions. Likewise, aspects of the disclosure can beincluded wherein the right engine system 34, or the generators 36, 38associated with the right engine 14, can be primarily responsible forsupplying a sufficient amount of energy for powering the “right” set ofelectrical buses 78, 80, 82, 84.

In one non-limiting example configuration or classification of theelectrical loads, the main bus can selectively enable or disable thepowering or energizing of main loads, including non-critical electricalloads. In another non-limiting example configuration or classificationof the electrical loads, the essential bus can selectively enable ordisable the powering or energizing of essential, or flight-criticalloads. As used herein “non-critical” electrical loads can includein-flight entertainment, galley functions, or the like, while“flight-critical” electrical loads can include flight management system,electrical flight actuators, or the like. In yet another non-limitingexample configuration or classification of the electrical loads, thepower conversion bus can selectively enable or disable additional powerconverting, similar to functions of the ICCs 40, 42, 64, 66, and thebattery bus can selectively enable or disable the powering, energizing,recharging, or receiving of stored energy, for example, by way of abattery, supercapacitor, or another power-supplying device.

Non-limiting aspects of the electrical power system architecture 30 canalso include a share regulator 69. The share regulator 69 can becommunicatively coupled with the first generator system 85, the secondgenerator system 87, the third generator system 89, the fourth generatorsystem 91, or a subset of generators systems providing power to thepower distribution bus 44. The share regulator 69 can also becommunicatively coupled with the left engine 12 and the right engine 14.Although the illustrated embodiment shows the positioning of the sharingregulator 69 separate from the left or right engine systems 32, 34,alternate positioning is envisioned. For instance, in one non-limitingexample configuration of the disclosure, the share regulator 69 can belocated remotely from the engine systems 32, 34, or multiple shareregulators can be positioned to correspond with each engine 12, 14, orto correspond with each generator 18, 19, 36, 38.

Non-limiting aspects of the disclosure can be included wherein the shareregulator 69 is configured to receive an operational status, or signalrepresentative thereof, from the left engine 12 or the right engine 14.As used herein, an operational status can include whether the engine 12,14 is currently operating (e.g. providing thrust or providing mechanicalenergy for operating the coupled set of generators 18, 19, 36, 38), orwhether the engine 12, 14 is not operating. Additional non-limitingaspects of the disclosure can be included wherein the share regulator 69is configured to provide a share ratio value, or a signal representativethereof, to the set or a subset of the first and second generatorsystems 85, 87, or to the set or subset of the third and fourthgenerator systems 89, 91. Stated another way, the share regulator 69 canbe configured to operably execute a power split ratio among the powersources based, as explained herein. In this sense, the set of generatorsystems 85, 87, 89, 91, or a subset thereof, can alter a correspondingpower output of the respective generator 18, 19, 36, 38, for example,via the respective ICC 40, 42, 64, 66, in response to the share ratiovalue provided by the share regulator 69. In another non-limiting aspectof the disclosure, the share regulator 69 is configured to furtherreceive a power output indicator, a desired power signal, a demandedpower signal, or signal representative thereof, from the communicativelyconnected generator systems 85, 87, 89, 91, representative of the powergenerated by the respective generator 18, 19, 36, 38.

In one non-limiting example, the share ratio values include a desiredpower signal such that the generator operably generates more or lesspower, compared with normal power generation operations. For instance,the share ratio values can include a desired power signal selected,configured, or generated to enable the set of generator systems 85, 87,89, 91 or the set of generators 18, 19, 36, 38, or a subset thereof, tooperate in overload mode (e.g. increasing power output) for a limitedperiod of time. The limited period of time can be based on, forinstance, the cooling capabilities of the generator 18, 19, 36, 38, thepower output of the generator 18, 19, 36, 38 during normal operation oroverload operation, the desired or demanded power as indicated by theshare ratio value or desired power signal, of the criticality of thedesired or demanded power. In one non-limiting aspect of the disclosure,a failed or non-operational engine in need of a restarting power supplycan have a high criticality for the desired power, resulting inoperating an operational generator 18, 19, 36, 38 or generator system85, 87, 89, 91 in overload operation, compared with a demand for adesired power for supplemental lighting. In one non-limited example,overload operation can for a period of time less than or equal to fiveminutes. In another non-limited example, overload operation can lastuntil the condition causing the need for excess power subsides or isrelieved.

Non-limiting aspects of the disclosure can be included wherein theelectrical power system architecture 30 described can be configured toallocate power among the generator systems 85, 87, 89, 91, or a subsetthereof, based on the share ratio value provided by the share regulator69. For instance, the share regulator 69 can be configured to provideinstruction to allocate power output between the first and secondgenerator system 85, 87 for operably powering the power distribution bus44 or a set or subset of electrical buses 71, such as the set of “left”buses 70, 72, 74, 76. Likewise, the share regulator 69 can be configuredto provide instruction to allocate power output between the third andfourth generator system 89, 91 for operably powering the powerdistribution bus 44 or a set or subset of electrical buses 71, such asthe set of “right” buses 78, 80, 82, 84.

The summation of the share ratio values represents the full desiredpower load for the power supplied by the respective left or right enginesystem 32, 34. Thus, the share ratio values can be any value between(and including) 0 and 1 representing the ratio of load handled by eachgenerator versus total respective load, such that the summation of theshare ratio values equals 1.0. Alternate share command values and rangesare envisioned. If there are more than two generators whose power is tobe allocated, then each share ratio value can be a fraction of 1, solong as the summation of all share ratio values equals 1.0. In additionto providing instruction on power output allocation between therespective generators 18, 19, 36, 38 or generator systems 85, 87, 89,91, the share regulator 69 can also be configured to receive the desiredpower signal from the generators 18, 19, 36, 38 or generator systems 85,87, 89, 91 to ensure or confirm the expected allocation of power isprovided.

Non-limiting aspects of the disclosure can be included wherein the shareregulator 69 can be configured to provide a share ratio value to thegenerator systems of an engine system (e.g. the third and fourthgenerators systems 89, 91 of the right engine system 34) to account fora particular operational circumstance, such as the operation oroperational status of another engine system (e.g. the left engine system32). For example, if the left engine 12 or left engine system 32 hasfailed, been damaged, been disabled, stalled, or is otherwisenon-operational, the share regulator 69 can enable, provide, or commandthe third generator 36, fourth generator 38, another generator, agenerator system 89, 91, or a combination thereof, to generate power inaccordance with a share ratio value corresponding to the non-operationalstatus of the left engine 12 or left engine system 32.

Although the first generator 18 is shown coupled with the HP spool 48,and the second generator 19 is shown coupled with the LP spool 50, it isenvisioned that any generator/spool combination can function similarly,e.g., the first generator system 18 can be coupled with the LP spool 50,and so on. Similar alternative generator/spool arrangements areenvisioned for the third and fourth generators 36, 38, or a combinationthereof. Moreover, the electrical power system architecture 30 can alsobe implemented on an engine 12, 14 or engine system 32, 34 having morethan two generators or more than two spools, such as a3-spool/3-generator engine having an intermediate pressure spool inaddition to the HP and LP spools.

Aspects of the disclosure can be included wherein an estimated,predetermined, or demanded amount of power is sufficient to supply thedesired operating condition of the aircraft or the engine systems 32,34, and shared between the set or a subset of operational generators 18,19, 36, 38. For example, the demanded power supply for a desiredoperating condition can be based on a number of factors, including, butnot limited to, a parasitic resistance of the respective generators 18,19, 36, 38 or desired electrical loads 70, 72, 74, 76, 78, 80, 82, 84,the expected current draw of the desired electrical loads 70, 72, 74,76, 78, 80, 82, 84, or the like.

The desired or demanded power allocation can be determined by manualinput, an executable computer program, an expected operatingcharacteristics of the gas turbine engines 12, 14, a referenced fromknown data such as a lookup table, or the like. The computer program caninclude a computer program product that can include machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media, which can be accessed by a general purpose or specialpurpose computer or other machine with a controller. Generally, such acomputer program can include routines, programs, objects, components,data structures, and the like, that have the technical effect ofperforming particular tasks or implement particular abstract data types.Machine-executable instructions, associated data structures, andprograms represent examples of program code for executing the exchangeof information as disclosed herein. Machine-executable instructions caninclude, for example, instructions and data, which cause a generalpurpose computer, special purpose computer, or special purposeprocessing machine to perform a certain function or group of functions.Aspects of the disclosure are envisioned wherein the share regulator 69can include a controller module configured for executing such computerprograms, and can additionally receive the operational data from acontrollable component, the control loop feedback mechanism, or from anexternal signal generated by, for example, the left or right engines 12,14, a set of the generators 18, 19, 36, 38, or a set of generatorsystems 85, 87, 89, 91.

During transient moments where the set of generators 18, 19, 36, 38 orgenerator systems 85, 87, 89, 91 do not confirm the desired powerallocation of the respective engine system 32, 34, the share regulator69 can further alter the share ratio values in order to modify the poweroutput of the respective generator.

Aspects of the disclosure can also be included wherein the shareregulator 69 or the share ratio values can vary over the flight phase ofthe aircraft. For example, in one set of non-limiting share ratiovalues, the share ratio power demand can be 50% of power supplied by thefirst generator system 85 and 50% of power supplied by the secondgenerator system 87, during a taxi phase, or taxiing of the aircraft. Inanother non-limiting example, the share ratio power demand can be 75% ofpower supplied by the first generator system 85 and 25% of powersupplied by the second generator system 87, during a take-off or a climbphase of the aircraft. In yet another non-limiting example, the shareratio power demand can be 50% of power supplied by the first generatorsystem 85 and 50% of power supplied by the second generator system 87,during a cruise phase of the aircraft. In yet another non-limitingexample, the share ratio power demand can be 25% of power supplied bythe first generator system 85 and 75% of power supplied by the secondgenerator system 87, during a descent phase of the aircraft. In yetanother non-limiting example, the share ratio power demand can be 50% ofpower supplied by the first generator system 85 and 50% of powersupplied by the second generator system 87, during a final approach orlanding phase of the aircraft.

While only the first and second generators system 85, 87 of the leftengine system 32 are referenced, similar share ratio values can beprovided with respect to the third and fourth generators systems 89, 91of the right engine system 34. In another non-limiting aspect, theaforementioned share ratio values can be described relative to the spoolof the engine 12, 14, as opposed to a particular generator 18, 19, 36,38 or generator system 85, 87, 89, 91. For example, the share ratiopower demand can be 75% of power supplied by the generator systemconnected with the HP spool 48, 56 and 25% of power supplied by thegenerator system connected with the LP spool 50, 58, during a take-offor a climb phase of the aircraft. The aforementioned example share ratiovalues assume all engine systems 32, 34 are operational, or that allgenerator systems 85, 87, 89, 91 are generating power as expected (i.e.“normal operation”). Actual power demand from the set of generators 18,19, 36, 38 or set of generator system 85, 87, 89, 91 can be differentfrom the aforementioned values. As used herein, the percentages can berelated to an amount of power demanded, current demanded, or the like.

FIG. 3 illustrates one non-limiting example operation of the electricalpower system architecture 130 described herein. The electrical powersystem architecture 130 is similar to the electrical power systemarchitecture 30; therefore, like parts will be identified with likenumerals increased by 100, with it being understood that the descriptionof the like parts of the electrical power system architecture 30 appliesto the electrical power system architecture 130, unless otherwise noted.One difference is that the left engine 112 or the left engine system 132is non-operational, as shown. In the illustrated example, the shareregulator 69 can receive the non-operational status from the left engine112, or can receive a desired power signal from at least one of thefirst or second generator 18, 19 indicating no or low power generation.The share regulator 69 can, in response, provide a set of share ratiovalues to the third generator system 89 and fourth generator system 91such that they generate a corresponding first power output (illustratedas arrow 180) and a second power output (illustrated as arrow 182),respectively, and provide the first and second power outputs 180, 182 tothe power distribution bus 44.

Non-limiting aspects of the disclosure can be included wherein the powerdistribution bus 44, or a controlling mechanism thereof, selectivelyoperates the set of selective coupling links 46 to selectively shed asubset of the electrical buses 71 associated with the left engine 112 orthe left engine system 132. In one non-limiting example, the left mainbus 70, the left power conversion bus 74, the left battery bus 76, or asubset thereof can be selectively disabled or disconnected from thepower distribution bus 44, for instance, by way of the selectivecoupling links 46. Aspects of the disclosure can be included wherein theessential buses 72, 80 can be required or necessarily powered during allflight operations, regardless of the operational status of therespective associated engine. In this sense, the left essential bus 72will be supplied power by the power distribution bus 44 despite the leftengine 112 or left engine system 132 being non-operational.

Thus, non-limiting aspects of the disclosure can be included wherein theoperating right engine 14 or right engine system 134, or generatorsystems 89, 91 thereof, can be controllably operated by way of the shareratio values provided by the share regulator 69 to operably generate andsupply respective power outputs 180, 182 to the power distribution bus44 that are sufficient to electrically power the left essential bus 72(supply power illustrated by arrow 186) in addition to the associatedright engine electrical buses 78, 80, 82, 84 (supply power illustratedby arrow 184), or a subset thereof. Stated another way, the allocatingof power by the third and fourth generator systems 89, 91, by the shareregulator 69, by the power distribution bus 44, or by a combinationthereof, can be based at least upon the combined power needs,requirements, desires, or summation thereof, of the associatedoperational engine's electrical buses 78, 80, 82, 84 or subset thereof,and the essential bus 72 of the non-operational engine. In this sense,at least one of the third or fourth generators 36, 38 or generatorsystems 89, 91 can be designed, selected, sized, or otherwiseselectively configured to operably generate a desired or demanded amountof electrical power to supply the desired operating conditionillustrated, as shared between the generators 36, 38, or generatorsystem 89, 91, as described herein.

FIG. 4 illustrates another non-limiting example operation of theelectrical power system architecture 230 described herein. Theelectrical power system architecture 230 is similar to the electricalpower system architecture 30, 130; therefore, like parts will beidentified with like numerals increased by 200, with it being understoodthat the description of the like parts of the electrical power systemarchitecture 30, 130 applies to the electrical power system architecture230, unless otherwise noted. One difference is that the left engine 212or the left engine system 232 is being restarted in a starting orrestarting mode. In this configuration, at least one of the first andsecond generators are a starter/generator (illustrated as firststarter/generator 218 and first generator system 285) and wherein thestarting left engine 212 is being electrically restarted by way of arestarting power supply (illustrated as arrow 288) being selectivelysupplied to the starter/generator 218 or generator system 285.

The share regulator 69 can, in response to the scenario depicted,provide a set of share ratio values to the third generator 36 and fourthgenerator 38, or respective generator systems 89, 91, such that theygenerate the corresponding first power output 180 and the second poweroutput 182, respectively, and provide the first and second power outputs180, 182 to the power distribution bus 44. Non-limiting aspects of thedisclosure can be included wherein the power distribution bus 44, or acontrolling mechanism thereof, selectively operates the set of selectivecoupling links 46 to selectively shed a subset of the electrical buses71 as described with reference to FIG. 3, while selectively supplyingpower 186 to the left essential bus 72 and supplying power 184 to theassociated right engine electrical buses 78, 80, 82, 84 or subsetthereof, as well as supplying restarting power 288 to the firststarter/generator 218. Stated another way, the allocating of power bythe third and fourth generators 36, 38 or generator systems 89, 91, bythe share regulator 69, by the power distribution bus 44, or by acombination thereof, can be based at least upon the combined powerneeds, requirements, desires, or summation thereof, of the associatedoperational engine's electrical buses 78, 80, 82, 84 or subset thereof,the essential bus 72 of the non-operational engine, and the starting orrestarting power 288 supplied to the non-operational engine. In thissense, at least one of the third or fourth generators 36, 38 orgenerator systems 89, 91 can be designed, selected, sized, or otherwiseselectively configured to operably generate a desired or demanded amountof electrical power to supply the desired operating conditionillustrated, as shared between the generators 36, 38, as describedherein.

In the restarting mode, the first starter/generator 218 or the first ICC40 can be configured to receive the restarting power 288 from the powerdistribution bus 244, the third generator 36, the fourth generator 38,or a combination thereof, and operates to initiate movement in the primemover of the first starter/generator 218, which in turn initiatesrotational movement in the starting left engine 212, for example, by wayof the corresponding gearbox 52, 54. In one non-limiting aspect of thedisclosure, the first ICC 40 can be configured to convert, alter,modify, or the like, the restarting power 288 received from the powerdistribution bus 44, the third generator 36, the fourth generator 38, ora combination thereof. In another non-limiting aspect of the disclosure,at least one of the first ICC 40, the first starter/generator 218, orthe share regulator 69 can operate a method of restarting the leftengine 212 or left engine system 232 according to a starting orrestarting method, predetermined profile, optimized operation, frequencystepping-operation, or by a dynamic feedback profile based on physicalor electrical characteristics of the first starter/generator 218, theleft engine 212, or a combination thereof.

Once the left engine 212 or left engine system 232 reaches a minimaloperating speed (e.g. engine light off speed), for instance, as definedby the starting or restarting method, at least one of the firststarter/generator 218 or the second generator 19 changes from startingmode to generating mode. When changed to the generating mode, at leastone of the first starter/generator 218 or the second generator 19returns to generating a power supply, and providing the power supply toa respective first or second ICC 40, 42, the power distribution bus 44,the set or a subset of electrical buses 71, or a combination thereof.

In one non-limiting aspect of the disclosure, when the left engine 212or left engine system 232 has been successfully restarted, the shareregulator 69 can be configured to provide respective share ratio valuesto the first starter/generator 218 and the second generator 19, asdescribed herein, in accordance with normal operation. In anothernon-limiting aspect of the disclosure when the left engine 212 or leftengine system 232 has been successfully restarted, the share regulatorcan be configured to provide respective share ratio values to the thirdand fourth generators systems 89, 91, in accordance with normaloperation. For example, the power output of the third and fourthgenerators 36, 38 or generator systems 89, 91 can be controllablyreduced due to the ceasing of supplying at least the restarting power288 or the left essential bus power supply 186. In yet anothernon-limiting aspect of the disclosure when the left engine 212 or leftengine system 232 has been successfully restarted, the powerdistribution bus 44 can selectively connect or re-energize thepreviously shed or disabled subset of electrical buses, including, butnot limited to, the left main bus 70, the left power conversion bus 74,and the left battery bus 76.

In one set of non-limiting share ratio values for restarting anon-operational engine, the share ratio power demand can be 25% of powersupplied by the third generator system 89 and 75% of power supplied bythe fourth generator system 91, during a taxi phase, or taxiing of theaircraft. In another non-limiting example, the share ratio power demandfor restarting a non-operational engine can be 50% of power supplied bythe third generator system 89 and 50% of power supplied by the fourthgenerator system 91, during a take-off or a climb phase of the aircraft.In yet another non-limiting example, the share ratio power demand forrestarting a non-operational engine can be 25% of power supplied by thethird generator system 89 and 75% of power supplied by the fourthgenerator system 91, during a cruise phase of the aircraft. In yetanother non-limiting example, the share ratio power demand forrestarting a non-operational engine can be 10% of power supplied by thethird generator system 89 and 90% of power supplied by the fourthgenerator system 91, during a descent phase of the aircraft. In yetanother non-limiting example, the share ratio power demand forrestarting a non-operational engine can be 25% of power supplied by thethird generator system 89 and 75% of power supplied by the fourthgenerator system 91, during a final approach or landing phase of theaircraft.

While the aforementioned example operation was described with referenceto the right engine 14 or right engine system 34 operating to supplyelectrical power while restarting the left engine 212 or left enginesystem 232, non-limiting aspects of the disclosure can be equallyapplied to any operational first engine or first engine system having aset of operational generators supplying a starting or restarting power288 to a non-operational second engine or second engine system. Inanother non-limiting aspect, the aforementioned share ratio values canbe described relative to the spool of the engine 12, 14, as opposed to aparticular generator 18, 19, 36, 38, 218. For example, the share ratiopower demand can be 25% of power supplied by the generator systemconnected with the HP spool 48, 56 and 75% of power supplied by thegenerator system connected with the LP spool 50, 58, during a take-offor a climb phase of the aircraft. Actual power demand from the set ofgenerators 18, 19, 36, 38, 218 or generator system 85, 87, 89, 91, 285can be different from the aforementioned values. As used herein, thepercentages can be related to an amount of power demanded, currentdemanded, or the like.

As previously described, aspects of the disclosure in accordance withFIG. 3 or FIG. 4 can include operating a set or subset of the generators18, 19, 36, 38 or generator systems 85, 87, 89, 91 in accordance with adesired power signal, to operate at above-normal, exceeded-rating, oroverload power generation modes.

FIG. 5 illustrates a flow chart demonstrating a method 300 forallocating power in an electrical power system architecture 30, 130,230. The method 300 begins by determining an operational status of firstengine 12, 14, 112, 212 or first engine system 32, 34, 132, 232 at 310.Next, in response to determining the first engine 12, 14, 112, 212 orfirst engine system 32, 34, 132, 232 is non-operational, selectivelydisconnecting a first set of electrical loads 70, 74, 76 associated withthe first engine system from a power distribution bus except for asubset of essential electrical loads associated with the first engine12, 14, 112, 212 or first engine system 32, 34, 132, 232 at 320. Themethod 300 then continues to providing a set of share ratio values to asecond operational engine 12, 14, 112, 212 or second engine system 32,34, 132, 232 having at least a first generator 18, 19, 36, 38 and asecond generator 18, 19, 36, 38, at 330. Next, the method 300 includesoperating the first and the second generators 18, 19, 36, 38 orgenerator systems 85, 87, 89, 91, 285 in accordance with the set ofshare ratio values such that the first and the second generators 18, 19,36, 38 or generator systems 85, 87, 89, 91, 285 allocate a desiredcombined power output to the power distribution bus 44 sufficient toenergize a second set of electrical loads 78, 80, 82, 84 associated withthe second engine 12, 14, 112, 212 or second engine system 32, 34, 132,232 and the subset of essential electrical loads 72 associated with thefirst engine 12, 14, 112, 212 or first engine system 32, 34, 132, 232.

FIG. 6 illustrates a flow chart demonstrating a method 400 forrestarting a non-operational engine 12, 14, 112, 212 of a flyingaircraft 10. The method 400 starts with disabling a set of electricalloads 70, 74, 76 associated with the non-operational engine 12, 14, 112,212 from a power distribution bus 44 except for a subset of essentialelectrical loads 72 associated with the non-operational engine 12, 14,112, 212 at 410. Next, the method 400 continues by selectivelyallocating a combined power output between at least two generators 18,19, 36, 38, 218 or generator systems 85, 87, 89, 91, 285 driven by atleast one operational engine 12, 14, 112, 212 in the flying aircraft 10,at 420. The method 400 then proceeds to restarting the non-operationalengine 12, 14, 112, 212 by way of a mechanically connectedstarter/generator 218 supplied with at least a portion of the combinepower output. The selectively allocating the combined power output isbased at least on the summation of a first power demand for a set ofelectrical loads associated 78, 80, 82, 84 with the operational engine12, 14, 112, 212, a second power demand for the subset of essentialelectrical loads 72 associated with the non-operational engine 12, 14,112, 212, and a third power demand for the restarting thenon-operational engine 12, 14, 112, 212.

The sequences depicted is for illustrative purposes only and are notmeant to limit the methods 300, 400 in any way as it is understood thatthe portions of the methods 300, 400 can proceed in a different logicalorder, additional or intervening portions can be included, or describedportions of the methods 300, 400 can be divided into multiple portions,or described portions of the methods 300, 400 can be omitted withoutdetracting from the described methods 300, 400.

Many other possible embodiments and configurations in addition to thatshown in the above figures are contemplated by the present disclosure.

The embodiments disclosed herein provide a method and system forallocating power in an electrical power system architecture. Thetechnical effect is that the above described embodiments enable theallocation of power output from operational generators, as well as thestarting or restarting of a non-operational generator. One advantagethat can be realized in the above embodiments is that the abovedescribed embodiments have superior weight and size advantages over theconventional type turbine generator systems, since the above describedembodiments can be selected, configured, tailored, or operated withknown, predetermined, or estimated power generation envelopes or ranges.Power rating of both HP and LP generator system can be significantlyreduced. This is because both HP and LP spool on operational engine willshare the power extraction needed to start the non-operational engine.Thus, the starting power draw each from side HP generator system and LPgenerator system of the operational engine is lower compared to if onlyone generator had to provide the full starting power.

With the proposed allocation between parallel configured generators, ahigh power output can be achieved without the need for a single largergenerator or larger mechanical driving force.

Another advantage that can be realized in the practice of someembodiments of the described systems and methods is that power can beextracted from two or more spools of an engine. The operating efficiencyof the engine is also increased by seamlessly controlling the powerdrawn from HP and LP (and possibly more) spools in various flightphases.

Actual power demand from HP and LP spool can be different than thesenotional values described above. This disclosure provides ability tooptimize the power draw or power generation from HP and LP spools duringany phase of the flight for in flight cross-engine starting orrestarting of a non-operational engine or engine system. Another benefitof the described aspects is that an aircraft employing such aspects canincrease the engine stall margin for corner point conditions on flightenvelope (e.g. high altitude, low Mach speed, etc.). For example, LPspool power extraction for an engine would enable power extraction inthe range of few hundred kilowatts to megawatts without compromising thestall margin. For instance, in the practice of some embodiments of thedescribed systems and methods is the avoidance of engine stall issuesthat are typically encountered during a descend mode of the aircraft bysharing the DC load between the HP and LP spools. Being able to drawpower from the LP spool as well as the HP spool permits allows theaircraft to run at engine idle speed lower rpms during descent withoutrisk of stall, thereby preserving fuel efficiency of the aircraft.

Yet another benefit of the above described aspects is that the powerallocation can be included wherein the essential electrical loads of thenon-operation engine can remain powered, energized, or the like, whileother non-essential electrical loads associated with the non-operationalengine can be shed. Thus, an aircraft employing the aspects of thedisclosure can operate with a full flight envelope of essentialelectrical loads operations regardless of the operational status of therespective or associated engine.

In another aspect of the disclosure, cross-starting of the enginedescribed herein can eliminate the need for electric start air turbinestarters.

To the extent not already described, the different features andstructures of the various embodiments can be used in combination witheach other as desired. That one feature cannot be illustrated in all ofthe embodiments is not meant to be construed that it cannot be, but isdone for brevity of description. Thus, the various features of thedifferent embodiments can be mixed and matched as desired to form newembodiments, whether or not the new embodiments are expressly described.Combinations or permutations of features described herein are covered bythis disclosure.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable of theinvention is defined by the claims, and can include other examples thatoccur to those skilled in the art. Such other examples are intended tobe within the scope of the claims if they have structural elements thatdo not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

Further aspects of the invention are provided by the subject matter ofthe following clauses:

1. A method for restarting a non-operational engine of a flyingaircraft, the method including disabling a set of electrical loadsassociated with the non-operational engine from a power distribution busexcept for a subset of essential electrical loads associated with thenon-operational engine, selectively allocating a combined power outputbetween at least two generator systems driven by at least oneoperational engine of the flying aircraft, and restarting thenon-operational engine by way of a mechanically connectedstarter/generator supplied with at least a portion of the combined poweroutput, wherein the selectively allocating the combined power output isbased at least on the summation of a first power demand for a set ofelectrical loads associated with the operational engine, a second powerdemand for the subset of essential electrical loads associated with thenon-operational engine, and a third power demand for the restarting thenon-operational engine.

2. The method of any preceding clause wherein the selectively allocatingthe combined power output includes providing at least one of a set ofshare ratio values or a desired power signal corresponds to a desiredcombined power output to the at least two generator systems.

3. The method of any preceding clause wherein the selectively allocatingthe combined power output is based upon the phase of flight of theaircraft.

4. The method of any preceding clause wherein providing includesproviding the set of share ratio values to a second operational enginesystem having at least the first generator system and the secondgenerator system.

5. The method of any preceding clause further comprising operating thefirst and the second generators in accordance with the set of shareratio values such that at least the first generator system and thesecond generator system allocate a desired combined power output to thepower distribution bus sufficient to energize the subset of essentialelectrical loads associated with the non-operational engine.

6. The method of any preceding clause wherein providing includesproviding a set of share ratio values based on a flight phase of anaircraft.

7. The method of any preceding clause, further including determining anoperational status of a first engine system, and in response todetermining the first engine system is non-operational, disabling theset of electrical loads associated with the non-operational engine,selectively allocating a combined power output, and restarting thenon-operational engine.

8. The method of any preceding clause wherein the operating includesaltering the power output of at least one of the at least two generatorsystems such that the at least one of the at least two generator systemsallocate the desired combined power output based on the desired powersignal.

9. The method of any preceding clause, wherein restarting thenon-operational engine includes the non-operational engine system havinga starter/generator mechanically connected with the non-operationalengine system by selectively supplying the at least a portion of thecombined power output from a power distribution bus to thestarter/generator, and operating the starter/generator in a startingmode.

10. The method of any preceding clause wherein selectively allocatingincludes operating the at least two generator systems such that thefirst and the second generators allocate a desired combined power outputto the power distribution bus sufficient to supply the at least aportion of the combine power to the starter/generator and operating thestarter/generator in the starting mode.

11. The method of any preceding clause wherein selectively allocatingincludes operate at least one of the at least two generators systems inoverload mode.

12. An electrical power system architecture, including a powerdistribution bus configured to receive power generated by a first enginehaving a first generator system and a second generator system, a firstset of electrical buses connected with the power distribution bus andassociated with the first engine, a second set of electrical busesconfigured to selectively connect with the power distribution bus,including at least an essential bus, and associated with a secondengine, and a share regulator configured to provide a set of shareratios values to the first generator system and the second generatorsystem, and configured to receive an operational status of the secondengine, wherein, upon receipt of non-operational status of the secondengine, the power distribution bus is configured to selectivelydisconnect the second set of electrical buses except for the essentialbus, and the share regulator is configured to provide the set of shareratio values to the first generator system and second generator systemselected to enabled the first and second generator systems to shareallocation of power generation sufficient to: energize the first set ofelectrical buses, energize the essential bus, and to restart thenon-operational second engine.

13. The electrical power system architecture of any preceding clausewherein the share regulator is configured to provide a desired powersignal to at least one of the first generator system or the secondgenerator system.

14. The electrical power system architecture of any preceding clausewherein the at least one of the first or the second generator systemsare configured to alter a power output in accordance with the desiredpower signal.

15. The electrical power system architecture of any preceding clausewherein the at least one of the first or the second generator systemsare configured to operate in overload mode in response to the desiredpower signal.

16. The electrical power system architecture of any preceding clausewherein the second engine includes a third generator system.

17. The electrical power system architecture of any preceding clausewherein the third generator system includes a starter/generator.

18. The electrical power system architecture of any preceding clausewherein, upon receipt of non-operational status of the second engine,the share regulator is configured to provide the set of share ratiovalues to the first generator system and the second generator system,wherein the share ratio values are selected to enabled the first andsecond generator systems to share allocation of power generationsufficient to energize the starting of the second engine by way of thestarter/generator system.

19. The electrical power system architecture of any preceding clausewherein at least one of the first or the second generator systems aremechanically connected to a high pressure spool in the first engine.

20. The electrical power system architecture of any preceding clausewherein at least one of the first or the second generator systems aremechanically connected to a low pressure spool in the first engine.

What is claimed is:
 1. A method for restarting a non-operational engineof a flying aircraft, the method comprising: disabling a set ofelectrical loads associated with the non-operational engine from a powerdistribution bus except for a subset of essential electrical loadsassociated with the non-operational engine; selectively allocating acombined power output between at least two generator systems driven byat least one operational engine of the flying aircraft; and restartingthe non-operational engine by way of a mechanically connectedstarter/generator supplied with at least a portion of the combined poweroutput; wherein the selectively allocating the combined power output isbased at least on the summation of a first power demand for a set ofelectrical loads associated with the operational engine, a second powerdemand for the subset of essential electrical loads associated with thenon-operational engine, and a third power demand for the restarting thenon-operational engine.
 2. The method of claim 1 wherein the selectivelyallocating the combined power output includes providing at least one ofa set of share ratio values or a desired power signal corresponds to adesired combined power output to the at least two generator systems. 3.The method of claim 2 wherein the selectively allocating the combinedpower output is based upon the phase of flight of the aircraft.
 4. Themethod of claim 2 wherein providing includes providing the set of shareratio values to a second operational engine system having at least thefirst generator system and the second generator system.
 5. The method ofclaim 4 further comprising operating the first and the second generatorsin accordance with the set of share ratio values such that at least thefirst generator system and the second generator system allocate adesired combined power output to the power distribution bus sufficientto energize the subset of essential electrical loads associated with thenon-operational engine.
 6. The method of claim 2 wherein providingincludes providing a set of share ratio values based on a flight phaseof an aircraft.
 7. The method of claim 1, further comprising:determining an operational status of a first engine system; and inresponse to determining the first engine system is non-operational,disabling the set of electrical loads associated with thenon-operational engine, selectively allocating a combined power output,and restarting the non-operational engine.
 8. The method of claim 7wherein the operating includes altering the power output of at least oneof the at least two generator systems such that the at least one of theat least two generator systems allocate the desired combined poweroutput based on the desired power signal.
 9. The method of claim 1,wherein restarting the non-operational engine includes thenon-operational engine system having a starter/generator mechanicallyconnected with the non-operational engine system by selectivelysupplying the at least a portion of the combined power output from apower distribution bus to the starter/generator, and operating thestarter/generator in a starting mode.
 10. The method of claim 9 whereinselectively allocating includes operating the at least two generatorsystems such that the first and the second generators allocate a desiredcombined power output to the power distribution bus sufficient to supplythe at least a portion of the combine power to the starter/generator andoperating the starter/generator in the starting mode.
 11. The method ofclaim 1 wherein selectively allocating includes operate at least one ofthe at least two generators systems in overload mode.
 12. An electricalpower system architecture, comprising: a power distribution busconfigured to receive power generated by a first engine having a firstgenerator system and a second generator system; a first set ofelectrical buses connected with the power distribution bus andassociated with the first engine; a second set of electrical busesconfigured to selectively connect with the power distribution bus,including at least an essential bus, and associated with a secondengine; and a share regulator configured to provide a set of shareratios values to the first generator system and the second generatorsystem, and configured to receive an operational status of the secondengine; wherein, upon receipt of non-operational status of the secondengine, the power distribution bus is configured to selectivelydisconnect the second set of electrical buses except for the essentialbus, and the share regulator is configured to provide the set of shareratio values to the first generator system and second generator systemselected to enabled the first and second generator systems to shareallocation of power generation sufficient to: energize the first set ofelectrical buses, energize the essential bus, and to restart thenon-operational second engine.
 13. The electrical power systemarchitecture of claim 12 wherein the share regulator is configured toprovide a desired power signal to at least one of the first generatorsystem or the second generator system.
 14. The electrical power systemarchitecture of claim 13 wherein the at least one of the first or thesecond generator systems are configured to alter a power output inaccordance with the desired power signal.
 15. The electrical powersystem architecture of claim 14 wherein the at least one of the first orthe second generator systems are configured to operate in overload modein response to the desired power signal.
 16. The electrical power systemarchitecture of claim 12 wherein the second engine includes a thirdgenerator system.
 17. The electrical power system architecture of claim16 wherein the third generator system includes a starter/generator. 18.The electrical power system architecture of claim 17 wherein, uponreceipt of non-operational status of the second engine, the shareregulator is configured to provide the set of share ratio values to thefirst generator system and the second generator system, wherein theshare ratio values are selected to enabled the first and secondgenerator systems to share allocation of power generation sufficient toenergize the starting of the second engine by way of thestarter/generator system.
 19. The electrical power system architectureof claim 12 wherein at least one of the first or the second generatorsystems are mechanically connected to a high pressure spool in the firstengine.
 20. The electrical power system architecture of claim 12 whereinat least one of the first or the second generator systems aremechanically connected to a low pressure spool in the first engine.